Exercise Increases Our Lifespan

Even a little exercise is enough to reduce the risk of an early death by as much as 30 percent, British researchers say. "Efforts to encourage small increases in physical activity in inactive individuals likely have significant health benefits," said lead author Ulf Ekelund, a senior scientist at the University of Cambridge. The report was published in January, 2015 in the American Journal of Clinical Nutrition.

The risk reduction was seen in normal weight, overweight and obese people, Ekelund said. "We estimated that eradicating physical inactivity in the population would reduce the number of deaths twice as much as if obesity was eradicated." In other words, exercise is more important than weight loss. The effect of moderate exercise was greatest among normal weight people, but even overweight and obese people saw a benefit.

For the study, Ekelund and his colleagues collected data from 334,000 men and women. Over an average of 12 years of follow-up, they measured height, weight, waist circumference and self-reported levels of physical activity. Ekelund's group found that a moderate amount of physical activity, compared with no activity, was the key to lowering the chances of premature death.

"The adaptations the body makes to regular exercise are nothing short of astounding," says Samantha Heller, a senior clinical nutritionist and exercise physiologist at New York University Medical Center. "Aerobic exercise ignites the body's immune system, improves mental function, boosts energy, strengthens muscles, and reduces the risk for chronic diseases such as heart disease, cancer and diabetes". Top

Daily Walking Extends Life

A brisk daily 20-minute walk could reduce the risk of an early death by almost a third, a recent study shows. Going for a short walk every day could add years to your life.
Lack of exercise is responsible for twice as many deaths as obesity. Brisk walking is just an example. Doing any exercise for 20 minutes a day is just as good.

A 20-minute walk at a vigorous pace, or a cycle ride of the same duration, would move an individual from being classed as inactive to moderately inactive. That change alone would reduce their risk of early death by between 16 and 30 per cent, Cambridge University researchers found. Exercise for 20 minutes is recommended as a minimum and when possible more extended exercise should be carried out for even greater benefits.

Even a small increase in physical activity each day like walking up escalators or using stairs instead of an elevator provides significant health benefits. Studying recent data on deaths in Europe, researchers estimated that 337,000 of the 9.2 million deaths of European men and women were linked to obesity. However, twice that number of deaths could be connected to lack of exercise.

Another study from Taiwan found that when compared to sedentary (not physically active) people, 15 minutes of brisk walking added three years to life expectancy. The researchers from Taiwan's National Health Research Institute published their findings in the medical journal Lancet. They tracked over 416,000 participants for 13 years, analyzing their health records and reported their levels of physical activity each year. Top

Physical Activity Slows Cellular Aging

Cells make up every organ in our bodies and the rate at which cells die varies with each individual. Various negative lifestyle factors (such as smoking) also greatly influence cellular aging.

Our cells contain telomeres, repetitive sections of DNA which are located at the ends of all chromosomes. See the red telomeres on the green chromosome cells in the photo to the left (photo has been colored for effectiveness). The telomeres protect the chromosomes from deterioration, which is similar to the way that shoelace tips protect laces from fraying.

As a person ages, the telomeres fray and become shorter and shorter as they divide (most cells divide 50 to 70 times before they die). See the illustration to the left below. Short telomeres have been linked to heart disease, cancer, and diabetes. The process is accelerated by obesity, smoking, insomnia, diabetes and other negative aspects of lifestyle. However, recent science suggests that exercise slows the decay of telomeres. Studies have found that athletes typically have longer telomeres than ordinary people of the same age.

The negative effects of a sedentary lifestyle on the cellular age of elderly women has been researched by a group at the University of California-San Diego. Researchers evaluated the link between sedentary time and the telomere length of 1,481 older women who were an average age of 79.

This was the first time that a study investigated the link between telomeres, sedentary time, and exercise. Small amounts of physical activity created a negative age gap of eight years between those women who exercised and those that did not. This study highlighted the importance of lifestyle choices because women who sat for a long time did not have shorter telomere lengths if they exercised according to the US National Guideline of at least 30 minutes a day. This study pointed out that physical activity should continue to be part of our daily lives even when we are 80 years old or older.Top

How Interval Training Helps Mitochondria Stave Off Aging

A study published in March, 2017 in "Cell Metabolism" found that exercise, and in particular aerobic exercise such as biking and walking, caused cells to make more protein for their energy producing mitochondria and effectively stop aging at the cellular level. Interval training involves a series of low to high intensity workouts interspersed with rest or low intensity periods.

Mitochondria, the energy factories of our cells, manufacture ATP to fuel all of life's activities. ATP (adenosine triphosphate) is produced in the mitochondria by a cell process combining oxygen with the energy stored in food. See the photo to the left of mitochondria in a cell. The number of mitochondria in a cell varies widely by cell type. For example red blood cells have no mitochondria, whereas liver cells can have more than 2000. A typical human cell will have on the order of 1,000 to 2,000 mitochondria.

The study enrolled 36 men and 36 women from two age groups - "young" volunteers who were 18-30 years old and "older" volunteers who were 65-80 years old. They were divided into three different exercise programs: one where the volunteers did high-intensity interval biking, one where the volunteers did strength training with weights, and one that combined strength training and interval training. Then the researchers, led by post-doc Matthew Robinson and colleagues, took biopsies from the volunteers thigh muscles and compared the molecular makeup of their muscle cells to samples from sedentary volunteers.

They found that while strength training was effective at building muscle mass, high-intensity interval training yielded the biggest benefits at the cellular level. The younger volunteers in the interval training group saw a 49% increase in mitochondrial capacity, and the older volunteers saw an even more dramatic 69% increase. Interval training also improved volunteers' insulin sensitivity, which indicates a lower likelihood of developing diabetes. However, interval training was less effective at improving muscle strength, which typically declines with aging. "If people have to pick one exercise, I would recommend high-intensity interval training, but I think it would be more beneficial if they could do 3-4 days of interval training and then a couple days of strength training," says Robinson. "But, of course, any exercise is better than no exercise."

As we age, the energy-generating capacity of our cells' mitochondria slowly decreases. The most impressive finding was the increase in muscle protein content. In some cases, the high-intensity biking regimen actually seemed to "reverse" the age-related decline in mitochondrial function and proteins needed for muscle building. The researchers also found a robust increase in mitochondrial protein synthesis. Increase in protein content explains enhanced mitochondrial function and muscle increase in bulk. Exercise's ability to transform these key elements could explain why exercise benefits our health in so many different ways. Top

Exercise Does "Not" Build Stronger Bones

Exercise has many benefits, but it does not build stronger bones. Many public health groups promote exercise as a prescription, promising it will stave off weak bones. But researchers know that advice is not backed up by rigorous studies.

The idea may have begun as an extrapolation of a well known fact: people who are bedridden lose bone mass. So do astronauts who spend time weightless. The pull of gravity seems to be needed for bone strength. Is there a threshold beyond which bones are about as strong as they will be from the force of gravity? Is everyday walking around just as good as running a marathon? The answers are yes, active adult physical activity has very little effect on the strength of bones versus inactivity. There is no evidence that bone strength is gained when people walk or run.

It is correct that exercise can help build strong bones in children and adolescents whose bones are still growing and developing, although there is uncertainty over what sort of exercise is best. However, an analysis that combined data from 43 randomized clinical trials concluded that while exercise had an insignificant effect on bone density (about 1% growth) there was no effect on the numbers of fractures. The study involved a total of 4,320 adult participants. Top

How Much Does Exercise Increase Our Lives?

Researchers from the Harvard affiliated Brigham and Women’s Hospital published an article which investigated the correlation between regular exercise and rates of mortality. See the chart to the left.

The graph indicates that moderate physical activity of 5 hours a week shows on average an increase of about 2.8 years of additional life (excluding additions from diet and other sources). Extreme activity of 26 hours a week (3+ hours a day) adds about 4.5 years to one's life. The U.S. Department of Health and Human Services (HHS) Guidelines recommend a minimum amount of adult (ages 18 to 64) exercise of 2.5 hours a week. This will add about 2 years to one's life.

Research studies for "older" adults (ages 65 and older) consistently show that activity performed on at least 3 days a week produces health benefits. Spreading physical activity across at least 3 days a week helps to reduce the risk of injury and avoids excessive fatigue. Episodes of aerobic activity count towards meeting the Guidelines if they last at least 10 minutes and are performed at moderate or vigorous intensity.

Here are the exact HHS Guidelines for older adults:

All older adults should avoid inactivity. Some physical activity is better than none, and older adults who participate in any amount of physical activity gain some health benefits.

For substantial health benefits, older adults should do at least 150 minutes (2 hours and 30 minutes) a week of moderate-intensity, or 75 minutes (1 hour and 15 minutes) a week of vigorous-intensity aerobic physical activity, or an equivalent combination of moderate- and vigorous-intensity aerobic activity. Aerobic activity should be performed in episodes of at least 10 minutes, and preferably, it should be spread throughout the week.

For additional and more extensive health benefits, older adults should increase their aerobic physical activity to 300 minutes (5 hours) a week of moderate-intensity, or 150 minutes a week of vigorous-intensity aerobic physical activity, or an equivalent combination of moderate- and vigorous-intensity activity. Additional health benefits are gained by engaging in physical activity beyond this amount.

Older adults should also do muscle-strengthening activities that are moderate or high intensity and involve all major muscle groups on 2 or more days a week, as these activities provide additional health benefits.